Thread: Character array problem

I am trying to solve this problem from K&R book.

Write a function reverse(s) that reverses the character string s. Use it to
write a program that reverses its input a line at a time.

My solution

Code:

#include <stdio.h>
#include <stdlib.h>
#define MAXLINE 10


void reverse(char r[], char s[]);

int main(void) {

	int i,c;
	char line[MAXLINE];
	char reversed[MAXLINE];

	for (i=0; i < MAXLINE && (c=getchar())!='X' && c!='\n'; ++i)
		line [i] = c;
	reverse (reversed,line);


	printf ("%s", reversed);

		return 0;
}




void reverse (char r[], char s[])
{
		int i=0;

		for (i=0; i<=10; i++)
			r[i]=0;

		while (i <= 10 && s[i] != '\0')
{
		r[10-i] = s[i];

		}
		++i;
}

The problem is...am not getting any output. I am guessing it's a concept problem with me but I am unable to figure it out. Any help please?

After this for-loop

Code:

for (i=0; i<=10; i++)
    r[i]=0;

i is 11.

Now look at the next line:

Code:

while (i <= 10 && s[i] != '\0')

The body of the while loop will never be executed.

You also have a buffer overflow because your valid indices are 0-9, thus you can't check if i <= 10.

And you should use the macro instead of 10.

Bye, Andreas

Whoops! HOW DID I MISS IT!!!?

Also I did an elementary mistake of keeping ++i outside the loop & it kept getting reseted to 0. Code works now!


Thanks hk_mp5kpdw, itsme86 & AndiPersti for all the help.